SYMPTOMS

RAS Monitor or other serial I/O software reports multiple cyclical redundancy check (CRC) errors and/or hardware overruns when transferring files or data over a serial connection. This problem occurs on your Windows NT 3.51 computer if you have installed Windows NT 3.51 and you are using the Atapi.sys device driver. The problem is more likely to occur if you have installed Service Pack 2 or 3.

NOTE: The Atapi.sys device driver is used for IDE CD-ROM drives and Enhanced IDE (EIDE) hard disks.

CAUSE

Hardware overrun problems are normally caused by a device driver keeping an interrupt disabled for too long. This was the case for the Atapi.sys interrupt service routine. The problem was aggravated by a change in Service Pack 2 and corrected in Service Pack 4.

WORKAROUND

To work around this problem, use the Atapi.sys device driver from the original Windows NT 3.51 distribution media or from Service Pack 4. Copy the appropriate Windows NT 3.51 Atapi.sys file to your %SystemRoot%\System32\Drivers directory.

IMPORTANT: This workaround should be used only if you do not require the updated Atapi.sys device driver included in Windows NT 3.51 Service Pack 2 for proper functionality of your EIDE hard disk. If you were not having problems with your EIDE hard disk before applying Windows NT 3.51 Service Pack 2, either Atapi.sys device driver suggested above may be used.

STATUS

Microsoft has confirmed this to be a problem in Windows NT 3.51. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Product Support Services for more information.